The preparation of new functionalised phthalocyanine compounds has been the subject
of intense research over the last three decades in order to develop new commercial
applications. Interestingly, their electrical and physical properties can be tuned by
suitable derivatization of their rigid inner core. A brief summary of the syntheses,
properties and applications of these compounds is described in Chapter 1.
The aim of this project was to synthesise new phthalocyanines for use in field effect
transistors (FETs). Chapter 2 describes the investigation of the preparation of novel
polysiloxane phthalocyanine polymers having hexyl substituents in non-peripheral
positions. It has been shown that polysiloxanes comprising non-peripherally substituted
phthalocyanines of this type cannot be isolated. Further investigation indicates that this
is likely to be due to steric hindrance. A series of mixed oligomeric compounds were
successfully synthesised by condensation of the corresponding substituted and
unsubstituted silicon phthalocyanine monomers. These co-oligomeric materials were
functionalised, isolated and characterised and found to exhibit interesting optical
properties. Moreover, the solid-state structure of a mixed phthalocyanine dimer was
determined by X-ray diffraction analysis. Interestingly, red fluorescence emission was
also exhibited by derivatives of these compounds.
During the preparation of a phthalocyanine intermediate, an unexpected coloured sideproduct
was also observed. The structure of this product proved to be closely related to
the phthalocyanine and was characterised as a tetrabenzotriazaporphyrin. The origin of
this by-product was explored. A series of metal-free and metallated derivatives of this
compound was subsequently prepared and their optical and physical properties
compared to their corresponding phthalocyanines. The results of these investigations are
reported in Chapter 3.